Rotation barriers around the carbene-metal bond of transition metal complexes of cycloheptatrienylidenes
作者:Frank J. Manganiello、Marc D. Radcliffe、W.M. Jones
DOI:10.1016/s0022-328x(00)84328-4
日期:1982.4
measured in the temperature range employed (RT to −105°C). The barrier in the benzannelated complex 12 is greater than in 11. This is consistent with Hoffmann's [2] prediction that an electronic component should contribute to conformational preferences and rotational barriers in carbene complexes of unsymmetrically substituted transition metals.
使用与温度相关的NMR研究,已经研究了铁的环庚三烯和三个环庚亚三烯基络合物的碳金属键周围的旋转。既不η 1 -cycloheptatrienylidene-η 5 -cyclopentadienyldicarbonyliron六氟磷酸盐(3),也不1,2-苯并-5-(η 5 -cyclopentadienylcarbonyltri正butylphosphineiron)环庚三烯(10)显示出任何温度的依赖关系到-105℃。由此得出的结论是,前者可能更喜欢电子上较不受欢迎的(但在空间上更受欢迎)的构象3b,而后者的旋转势垒太小而无法在此温度范围内观察到。两个η 1 -cycloheptatrienylidene-η5 -cyclopentadienylcarbonyltri正butylphosphineiron六氟磷酸盐(11)和η 1 -4,5- benzocycloheptatrienylidene-η